Like other metals, aluminium too can be painted. However, it is a trickier process with aluminium than with other metals, due to the fact that aluminium is a non-ferrous metal. Painting anodised aluminium proves even trickier. Find out here how to proceed in order to achieve the best possible results.
How can you paint aluminium?
Preparation is key when it comes to painting aluminium. For further information on the correct way to clean aluminium, click here. However, when it comes to painting aluminium we need to go one step further. The difficult thing about aluminium is the oxide layer. Similar to bonding aluminium, the oxide layer must be completely removed to avoid problems with the adhesion of the paint. There are a variety of options for removing this layer:
- Chemical removal
Sandpapering is the easiest way to process the aluminium. Please note that the surface will become rougher, depending on the grit of your sandpaper. You are advised to use two different grades of sandpaper. To start with, use a 400-grit sandpaper in order to completely remove the oxide layer. Then, for polishing, use a 1,000-grit sandpaper in order to smooth out the irregularities as far as possible.
For sandblasting or the chemical removal of the oxide layer you need the help of specialist aluminium processors or fabricators. However, please note that sandblasting severely roughens the surface.
After cleaning, any residues such as sandpaper particles must be removed from the material. Similar to the paintbrush hairs often seen in the paint on painted wood, on aluminium you would see each and every grain of dust. For this reason, it is recommended to re-polish the aluminium using a microfibre cloth or something similar just before applying the paint.
In order for the paint to adhere, you need to paint the aluminium with a primer before application. A bonding agent provides the required adhesive substrate. You can either spray it on directly or apply it using a paintbrush. Pay special attention to the removal of any residues from the paintbrush.
Varnishing or painting aluminium
As soon as the primer is dry, you can apply the paint of your choice. You are advised to proceed according to the information provided by the manufacturer. Unless specified otherwise, a final coat of varnish as a sealant is advised for aluminium. This is already contained in two-component paints. If not, it can be applied separately. Here too, it is important to ensure the mutual compatibility of the products used. Then all you need to do is wait for the paint to dry.